1. Field of the Invention
The invention relates to a novel fingerprint powder usable in the customary manner by sprinkling on latent prints, brushing off surplus and taking an impression by means of a tape, as well as by photographing. The invention further relates to methods of mixing the novel powder composition and to storing the composition under conditions where it can be used as affectively at a later time as when freshly made.
2. Description of the Prior Art
In Hedrick, U.S. Pat. No. 1,259,981, the standard black fingerprint powder is described as a combination of lamp black and gum adhesive and the use of the powder for taking prints is also taught employing the technique of spraying the print after dusting with an alcohol solvent to dissolve the gum.
In White, U.S. Pat. No. 1,539,448, the use of a variety of differently colored print powders, each in its own container, is taught as an improvement for detecting latent prints left on a variety of surfaces.
In Pitman, U.S. Pat. No. 1,951,203, the use of aluminum powder as a highly reflective component of the powder is disclosed.
In Fonda, U.S. Pat. No. 2,447,322, iron compounds are disclosed at column 2, line 5, as storage agents to retard the exhaustion of infra-red luminescence. At column 2, lines 35 et seq., manganese compounds are disclosed as activating agents for such storage.
In Terek, U.S. Pat. No. 2,986,831, print powders based on lamp black or aluminum are used to make transfer prints or photographs.
Similarly, in Bonora, U.S. Pat. No. 3,075,852, either carbon black or aluminum powder is used to make prints.
Each of the above black fingerprint powders has the disadvantage of requiring a cumbersome variety of mixtures in containers and applicators and of further requiring a high degree of skill is using these multiple containers and applicators.